The paper deals with the main contribution of the Finnish logician Jaakko Hintikka: epistemic logic, in particular the 'static' version of the system based on the formal analysis of the concepts of knowledge and belief. I propose to take a different look at this philosophical logic and to consider it from the opposite point of view of the philosophy of logic. At first, two theories of meaning are described and associated with two competing theories of linguistic competence. In a second (...) step, I draw the conclusion that Hintikka's epistemic logic constitutes a sort of internalisation of meaning, by the introduction of epistemic modal operators into an object language. In this respect, to view meaning as the result of a linguistic competence makes epistemic logic nothing less than a logic of unified meaning and understanding. (shrink)

Attention to the conversational role of alethic terms seems to dominate, and even sometimes exhaust, many contemporary analyses of the nature of truth. Yet, because truth plays a role in judgment and assertion regardless of whether alethic terms are expressly used, such analyses cannot be comprehensive or fully adequate. A more general analysis of the nature of truth is therefore required – one which continues to explain the significance of truth independently of the role alethic terms play in discourse. We (...) undertake such an analysis in this paper; in particular, we start with certain elements from Kant and Frege, and develop a construct of truth as a normative modality of cognitive acts (e.g., thought, judgment, assertion). Using the various biconditional T-schemas to sanction the general passage from assertions to (equivalent) assertions of truth, we then suggest that an illocutionary analysis of truth can contribute to its locutionary analysis as well, including the analysis of diverse constructions involving alethic terms that have been largely overlooked in the philosophical literature. Finally, we briefly indicate the importance of distinguishing between alethic and epistemic modalities. (shrink)

One of the most striking differences between Frege's Begriffsschrift (logical system) and standard contemporary systems of logic is the inclusion in the former of the judgement stroke: a symbol which marks those propositions which are being asserted , that is, which are being used to express judgements . There has been considerable controversy regarding both the exact purpose of the judgement stroke, and whether a system of logic should include such a symbol. This paper explains the intended role of the (...) judgement stroke in a way that renders it readily comprehensible why Frege insisted that this symbol was an essential part of his logical system. The key point here is that Frege viewed logic as the study of inference relations amongst acts of judgement , rather than – as in the typical contemporary view – of consequence relations amongst certain objects (propositions or well-formed formulae). The paper also explains why Frege's use of the judgement stroke is not in conflict with his avowed anti-psychologism, and why Wittgenstein's criticism of the judgement stroke as 'logically quite meaningless' is unfounded. The key point here is that while the judgement stroke has no content , its use in logic and mathematics is subject to a very stringent norm of assertion. (shrink)

Assertion plays a crucial dual role in Frege's conception of logic, a formal and a transcendental one. A recurrent complaint is that Frege's inclusion of the judgement-stroke in the Begriffsschrift is either in tension with his anti-psychologism or wholly superfluous. Assertion, the objection goes, is at best of merely psychological significance. In this paper, I defend Frege against the objection by giving reasons for recognising the central logical significance of assertion in both its formal and its transcendental role.

In the explanations of logical laws and inference rules of the mature version of Begriffsschrift in Grundgesetze, Frege uses the predicate “… is the True.” Scholars like Greimann maintain that this predicate is a metalinguistic truth-predicate for Frege. This paper examines an argument for this claim that is based on the “nominal reading” of Frege’s conception of sentences—the claim that for Frege a sentence “p” is equivalent to a nonsentential phrase like “the truth-value of the thought that p.” In particular, (...) this paper attempts to establish two points concerning this argument based on the nominal reading. First, the argument implies a claim about the nature of assertion which Frege repeatedly denies in his mature works. Secondly, the nominal reading on which the argument depends is false. A sentence “p” is not equivalent to a nonsentential phrase like “the truth-value of the thought that p” for Frege. Our discussion will lead to an important lesson about Frege’s conception of sentences and of assertion. (shrink)

It is argued that we should distinguish ontic truth––the True––that Frege claimed is sui generis and indefinable, from the semantic concept, for which Tarski provided a definition. Frege’s argument that truth is not definable is clarified and Wittgenstein’s introduction of the distinction between saying and showing is interpreted as an attempted response to Frege’s rejection of the correspondence theory. It is argued that conflicts between realism and Dummettian anti-realism result from their proponents not thoroughly distinguishing between the two closely connected (...) ways of thinking about truth. Last, the distinction is used to clarify and endorse the Fregean claim that all true sentences indicate the True, identified as ontic truth. (shrink)

The purpose of this paper is to reconstruct Frege’s argument against the relativity of truth contained in his posthumous writing Logic from 1897. Two points are made. The first is that the argument is a performative version of the common objection that truth relativism is incoherent: it is designed to show that the assertion of the relativity of truth involves a performative incoherence, because the absoluteness of truth is a success condition for making assertions. From a modern point of view, (...) the central premise of the argument, that the successful making of assertions depends on the absoluteness of truth, is highly doubtful. The second point is that this premise can be made plausible within the framework of Frege’s conception of truth and assertion: it can be derived from his thesis that, in order to put something forward as true, we do not need the word ‘true’, but only the assertoric force. (shrink)

ABSTRACT In “Die Verneinung”, Frege discusses two types of negation, a semantic one and a pragmatic one. Semantic negation consists in the application of the logical function denoted by ‘it is false that p’ to a thought, and pragmatic negation in the act of asserting or judging a thought as false. According to the standard interpretation, Frege does not acknowledge pragmatic negation, because it is logically redundant. He therefore rejects the classical dualistic view that both truth and falsity are qualities (...) of judgement and adopts instead the monistic view that to judge is always to recognize a thought as true. My aim in this paper is to show that this interpretation cannot be sustained. Though Frege does not endorse the classical view, he defends a dualistic conception that is characterized by the claim that judging is a binary operation that contains both the act of recognizing a thought as true and the act of rejecting the opposite thought as false. To make this interpretation plausible, Frege’s dualistic remarks on negation in three posthumous writings, which have received little attention so far, are analyzed in detail and their background is reconstructed. It is argued that Frege acknowledges negative judgements to account for the epistemic role of the act of judgement in the acquisition of knowledge. RESUMO Frege discute dois tipos de negação em “Die Verneinung” : uma semântica e uma pragmática. Negação semântica consiste na aplicação da função lógica denotada por ‘é falso que p’ para um pensamento, e negação pragmática no ato de afirmar ou julgar um pensamento como falso. De acordo com a interpretação padrão, Frege não reconhece a negação pragmática, porque ela é logicamente redundante. Assim, ele rejeita a visão dualística clássica de que tanto verdade quanto falsidade são qualidades de julgamento e, em vez disso, adota a visão monística de que julgar é sempre reconhecer um pensamento como verdade. Meu objetivo neste artigo é mostrar que tal interpretação não pode ser sustentada. Apesar de Frege não endossar a visão clássica, ele defende um conceito dualista que é caracterizado pela afirmação de que julgar é uma operação binária que contém tanto o ato de reconhecer um pensamento como verdade, quanto o ato de rejeitar o pensamento oposto como falso. Para tornar essa interpretação plausível, Frege faz observações dualísticas sobre a negação em três escritos póstumos, que têm recebido pouca atenção até o presente, são analisadas em detalhe e seu background é reconstruído. Argumenta-se que Frege reconhece o julgamento negativo para explicar o papel epistêmico do ato de julgar na aquisição de conhecimento. (shrink)

In a posthumous text written in 1915, Frege makes some puzzling remarks about the essence of logic, arguing that the essence of logic is indicated, properly speaking, not by the word ‘true’, but by the assertoric force. William Taschek has recently shown that these remarks, which have received only little attention, are very important for understanding Frege's conception of logic. On Taschek's reconstruction, Frege characterizes logic in terms of assertoric force in order to stress the normative role that the logical (...) laws play vis-à-vis judgement, assertion and inference. My aim in this paper is to develop and defend an alternative reconstruction according to which Frege stresses that logic is not only concerned with ‘how thoughts follow from other thoughts’, but also with the ‘step from thought to truth-value’. Frege considers logic as a branch of the theory of justification. To justify a conclusion by means of a logical inference, the ‘step from thought to truth-value’ must be taken, that is, the premis.. (shrink)

The aim of this paper is to give a detailed reconstruction of Frege's solution to his puzzle about the cognitive function of truth, which is this: On the one hand, the concept of truth seems to play an essential role in acquiring knowledge because the transition from the mere hypothetical assumption that p to the acknowledgement of its truth is a crucial step in acquiring the knowledge that p, while, on the other hand, this concept seems to be completely redundant (...) because the sense of the word 'true' does not make any essential contribution to the senses of the sentences in which it occurs. (shrink)

Joan Weiner has recently claimed that Frege neither uses, nor has any need to use, a truth-predicate in his justification of the logical laws. She argues that because of the assimilation of sentences to proper names in his system, Frege does not need to make use of the Quinean device of semantic ascent in order to formulate the logical laws, and that the predicate ‘is the True’, which is used in Frege's justification, is not to be considered as a truth-predicate, (...) because it does not apply to true sentences or true thoughts. The present paper aims to show that Frege needs to use, and does use, a truth-predicate in this context. It is argued, first, that Frege needs to use a truthpredicate in order to show that the truth of the logical laws is evident from the senses of the sentences by means of which they are formulated, and second, that the predicate that he actually uses, ‘is the True’, must be considered as a truth-predicate in the relevant sense, because it can be used and is actually used by Frege to explain the truth-conditions of thoughts. To defend this interpretation, it is discussed whether the explanatory use of ‘is the True’ in Frege's system is compatible with his deflationary analysis of ‘true’. The paper's conclusion is that there is indeed a conflict here; but, from Frege's point of view, this conflict is due merely to the logical imperfection of natural language and does not affect the proper system but only its propaedeutic. (shrink)

É comumente aceito, atualmente, que Aristóteles não teria enfrentado ou tentado seriamente resolver o famoso paradoxo do mentiroso, embora ele tenha sido formulado por Eubúlides de Mileto, membro da escola megárica e rival filosófico de Aristóteles. No máximo, assim reza a visão tradicional, ele parece apenas fazer uma menção desse paradoxo nas Refutações sofísticas, Capítulo 25, talvez esboçando a sua solução. O meu intento, no presente artigo, é desafiar essa opinião geral mostrando que o Estagirita fornece uma explicação implícita para (...) duas versões do paradoxo do mentiroso, a saber, a versão autorreferencial, e a versão anafórica. A minha alegação é que a solução aristotélica para essas duas versões do paradoxo encontra-se no núcleo de sua refutação de duas teses, as quais denominei como tese da synalethia e como tese da sympseudia. Tal refutação é realizada no oitavo capítulo do quarto Livro da Metafísica, um texto até agora subestimado pelos intérpretes modernos, mesmo sendo a parte final de um dos mais importantes escritos de Aristóteles. A solução aristotélica, assim defendo, é levada a cabo por meio dos seguintes princípios: toda declaração é sempre precedida por um operador de verdade da forma ‘é verdade que...’, ou seja, toda declaração, qualquer que seja o que ela possa declarar a mais, primariamente assevera a sua própria verdade; e, em conformidade com o princípio anterior, toda declaração que assevera a sua própria falsidade ou acarreta a verdade de sua contraditória é necessariamente falsa. Através desses princípios, a refutação de Aristóteles da synalethia e da sympseudia é bem-sucedida. Mostrarei que obtemos uma boa solução para as versões do mentiroso acima mencionadas, apenas aplicando esses mesmos princípios a elas. Esse tipo de solução ao mentiroso tanto quanto para as teses antes citadas é muito parecido com aquele explicitamente encontrado nas obras de diversos filósofos, a saber, Guilherme de Sherwood, Tomás Bradwardine, João Buridano, Alberto da Saxônia, Paulo Venetus, Charles S. Peirce e Arthur Prior. Assim, também defendo que essa linhagem tem as suas raízes na solução de Aristóteles. (shrink)

W latach 1893 i 1903 ukazały się dwa tomy najważniejszego dzieła Fregego Grundegezte der Arithmetik. Ten okres można nazwać „szczytem logicyzmu” Fregego. Chociaż temat prawdy w logiczno-filozoficznej twórczości Fregego był podejmowany wielokrotnie, to brakuje pozycji skupiającej się na badaniu poglądów w tym okresie. Dotyczy to w szczególności literatury polskiej. Moim zadaniem jest zebranie i uporządkowanie wszystkich wypowiedzi Fregego na temat prawdy w okresie wydawania wspomnianych tomów. Realizując to zadanie, badam użycie tego pojęcia w pierwszym tomie Grundegezte der Arithmetik oraz w (...) niepublikowanym tekście Logik. Podejmuję zagadnienie funkcjonowania tego terminu w szczególnych kontekstach: antynomii, geometrii i wyrażania ogólności. Na koniec zasygnalizuję kwestię sposobu rozumienia późniejszych wypowiedzi Fregego na temat prawdy. (shrink)

In 1893 and 1903, two volumes of the most important of Frege’s works Grundegezte der Arithmetik were published. This period can be called the peak of Frege’s logicism. Although the subject of truth in Frege’s logical and philosophical works has been repeatedly investigated, there is a lack of studies on his view in this period, especially in Polish literature. In this article, therefore, I carry out the following research task: to collect and order Frege’s statements about truth during the period (...) of publishing the two volumes of Grundegezte der Arithmetik. I refer to the texts published during Frege’s life, published posthumously and his correspondence. Particularly noteworthy are: Grundegezte der Arithmetik and the unpublished Logik. That is why there are two separate sections dedicated to these two texts, whereas the discussions of truth from other texts are grouped thematically: the problem of antinomy, geometry, expression of generality, and others. The subject of truth appears there in relation to logic, philosophy of language, philosophy of logic, philosophy of mathematics and ontology. (shrink)